Ki-67, Bcl-2 and p53 expression in primary and metastatic melanoma

The Analysis of bcl-2 in Association with p53 and Ki-67 in Triple Negative Breast Cancer and Other Molecular Subtypes in Ghana

BACKGROUND

Little is known about the role of apoptosis in the tumorigenesis and prognosis of breast cancer in Ghana. Chemotherapeutic drug efficacy partially relates to apoptosis induction, rendering it a vital target in cancer therapy with unique biomarker opportunities that have not been exploited. Aberrations in this pathway are central to tumorigenesis, tumor progression, overall tumor growth, and regression during treatment therapies. Antiapoptotic bcl-2 (gene) and p53 are known to play roles in apoptosis while Ki-67 is a proliferative marker. The aim of our study is to determine the association of bcl-2 (protein) with p53 and Ki-67 in 203 consecutive breast cancer cases over a 10-year period.

METHOD

A retrospective cross-sectional study on archival FFPE tissue blocks over a 9-year period with abstraction of clinicopathologic data. Two hundred and three consecutive and suitable FFPE blocks were selected for tissue microarray (TMA) construction, and IHC (bcl-2 (protein), Ki-67, p53, cyclin D, pan cytokeratins A and E, ER, PR, and HER2/neu) was done. Expressions of bcl-2 (protein), p53, and Ki-67 were related to histological grade, lymphovascular invasion, and molecular subtypes. SPSS version 23 was used to analyze results.

RESULTS

Most of our cases were in the fifth decade of life (31%); invasive carcinoma of no special type (NST) was predominant (87%); histological grade III (38%) was the highest; and Luminal A (19.8%), Luminal B (9.9%), HER2 (16%), and TNBC (54.3%) constituted the molecular classes. bcl-2 expression was found in 38% of the cases. Our cases also showed mutation in p53 (36.7%) and ki-67 expression (62.5%). bcl-2 (protein) and p53 significantly correlated with Luminal B and TNBC (p < 0.01). Ki-67 also correlated significantly with Luminal A and B and HER2 overexpression (p < 0.01). Premenopausal age (40-49) and histological grade inversely correlated with bcl-2 (protein) expression. p53 statistically correlated with Ki-67 (p < 0.05).

CONCLUSION

Our results show high expression of bcl-2 (protein) suggesting an important role of apoptosis in Ghanaian breast cancer cases. bcl-2 (protein), p53, and Ki-67 expressions emerged interdependently from this research and can thus be manipulated in prediction and prognosis of breast cancers in our setting.

Ferrocifen Loaded Lipid Nanocapsules: A Promising Anticancer Medication against Multidrug Resistant Tumors

Resistance of cancer cells to current chemotherapeutic drugs has obliged the scientific community to seek innovative compounds. Ferrocifens, lipophilic organometallic compounds composed of a tamoxifen scaffold covalently bound to a ferrocene moiety, have shown very interesting antiproliferative, cytotoxic and immunologic effects. The formation of ferrocenyl quinone methide plays a crucial role in the multifaceted activity of ferrocifens. Lipid nanocapsules (LNCs), meanwhile, are nanoparticles obtained by a free organic solvent process. LNCs consist of an oily core surrounded by amphiphilic surfactants and are perfectly adapted to encapsulate these hydrophobic compounds. The different in vitro and in vivo experiments performed with this ferrocifen-loaded nanocarrier have revealed promising results in several multidrug-resistant cancer cell lines such as glioblastoma, breast cancer and metastatic melanoma, alone or in combination with other therapies. This review provides an exhaustive summary of the use of ferrocifen-loaded LNCs as a promising nanomedicine, outlining the ferrocifen mechanisms of action on cancer cells, the nanocarrier formulation process and the in vivo results obtained over the last two decades.

Relevance of 2'-O-Methylation and Pseudouridylation for the Malignant Melanoma

Simple Summary

This study investigates the expression, the histological localization, and the influence of the factors involved in 2′-O-methylation and pseudouridylation on prognostic relevant markers, proliferation markers, overall survival, molecular immune surveillance and evasion mechanisms within the malignant melanoma. Statistically significant positive correlations to the expression of markers involved in cell proliferation were observed. The upregulation of the RNA modifying factors was of prognostic relevance in this tumor disease with a negative impact on the overall survival of melanoma patients. Furthermore, the factors involved in 2′-O-methylation and pseudouridylation were statistically significant negative correlated to the expression of human leukocyte antigen class I genes as well as of components of the antigen processing machinery.

Abstract

The two RNA modifications 2′-O-methylation and pseudouridylation occur on several RNA species including ribosomal RNAs leading to an increased translation as well as cell proliferation associated with distinct functions. Using malignant melanoma (MM) as a model system the proteins mediating these RNA modifications were for the first time analyzed by different bioinformatics tools and public available databases regarding their expression and histological localization. Next to this, the impact of these RNA-modifying factors on prognostic relevant processes and marker genes of malignant melanoma was investigated and correlated to immune surveillance and evasion strategies. The RNA modifying factors exerted statistically significant positive correlations to the expression of genes involved in cell proliferation and were statistically significant negative correlated to the expression of human leukocyte antigen class I genes as well as of components of the antigen processing machinery in malignant melanoma. Upregulation of the RNA modifying proteins was of prognostic relevance in this tumor disease with a negative impact on the overall survival of melanoma patients. Furthermore, the expression of known oncogenic miRs, which are induced in malignant melanoma, directly correlated to the expression of factors involved in these two RNA modifications.

New insights into the roles of antiapoptotic members of the Bcl-2 family in melanoma progression and therapy

Prosurvival and antiapoptotic B cell lymphoma-2 (Bcl-2) family proteins are often overexpressed in cutaneous melanoma, one of the most aggressive types of human cancer. They are also implicated in resistance to therapy and participate in melanoma progression by regulating various processes, including cell proliferation, migration, invasion, and crosstalk with the tumor microenvironment. In this review, we summarize recent findings related to prosurvival members of the Bcl-2 family beyond their canonical functions in the apoptotic pathway, mainly focusing on their potential roles as diagnostic and prognostic biomarkers in cutaneous melanoma. We also provide an overview of different approaches used to inhibit Bcl-2 proteins in preclinical and clinical studies, which are mainly based on the inhibition of protein expression or the disruption of their antiapoptotic functions.

Expression of Glut-1 in Malignant Melanoma and Melanocytic Nevi: an Immunohistochemical Study of 400 Cases

The glucose transporter-1 (Glut-1) is a cell membrane glycoprotein involved in glucose uptake. An increased expression of Glut-1 is an important cell adaptation mechanism against hypoxia. An upregulation of Glut-1 can be found in several types of malignant tumors, which are able to reprogram their metabolism from oxidative phosphorylation to aerobic glycolysis (Warburg effect). However, the data regarding melanocytic lesions is equivocal. We performed comprehensive immunohistochemical analysis of the Glut-1 expression in 225 malignant melanomas (MM) and 175 benign nevi. Only the membranous expression of Glut-1 was regarded as positive. The expression of Glut-1 (the cut-off for positivity was determined as H-score 15) was found in 69/225 malignant melanomas. The number of positive cases and the H-score of Glut-1 increased where there was a higher Breslow thickness (p < 0.00001) when comparing pT1- pT4 MM groups. All benign nevi were classified as negative. In conclusion, the membranous expression of Glut-1 is a common feature of a malignant melanoma but this type of expression is very rare in benign melanocytic nevi. Our results suggest that the membranous expression of Glut-1 can be used as a surrogate marker in the assessing of the biological nature of benign and malignant melanocytic lesions. However, despite its high specificity, the sensitivity of this marker is relatively low. Moreover, due to the fact that the increased expression of Glut-1 correlates with a shorter survival period (10-year disease free survival, recurrence free survival and metastasis free survival and MFS), it can be used as a prognostically adverse factor.

Efficient ferrocifen anticancer drug and Bcl-2 gene therapy using lipid nanocapsules on human melanoma xenograft in mouse

Metastatic melanoma has been described as a highly aggressive cancer with low sensibility to chemotherapeutic agents. New types of drug, such as metal-based drugs (ferrocifens) have emerged and could represent an alternative for melanoma treatment since they show interesting anticancer potential. Furthermore, molecular analysis has evidenced the role of apoptosis in the low sensibility of melanomas and especially of the key regulator, Bcl-2. The objective of this study was to combine two strategies in the same lipid nanocapsules (LNCs): i) gene therapy to modulate anti-apoptotic proteins by the use of Bcl-2 siRNA, and ii) ferrocifens as a new type of anticancer agent. The efficient gene silencing with LNCs was verified by the specific extinction of Bcl-2 in melanoma cells. The cellular toxicity of ferrocifens (ferrociphenol (FcDiOH) or Ansa-FcDiOH) was demonstrated, showing higher efficacy than dacarbazine. Interestingly, the association of siBcl-2 LNCs with Ansa-FcDiOH demonstrated a significant effect on melanoma cell viability. Moreover, the co-encapsulation of siRNA and ferrocifens was successfully performed into LNCs for animal experiments. A reduction of tumor volume and mass was proved after siBcl-2 LNC treatment and Ansa-FcDiOH LNC treatment, individually (around 25%). Finally, the association of both components into the same LNCs increased the reduction of tumor volume to about 50% compared to the control group. In conclusion, LNCs appeared to provide a promising tool for the co-encapsulation of a metal-based drug and siRNA.

Oncogenic BRAF induces chronic ER stress condition resulting in increased basal autophagy and apoptotic resistance of cutaneous melanoma

The notorious unresponsiveness of metastatic cutaneous melanoma to current treatment strategies coupled with its increasing incidence constitutes a serious worldwide clinical problem. Moreover, despite recent advances in targeted therapies for patients with BRAF(V600E) mutant melanomas, acquired resistance remains a limiting factor and hence emphasises the acute need for comprehensive pre-clinical studies to increase the biological understanding of such tumours in order to develop novel effective and longlasting therapeutic strategies. Autophagy and ER stress both have a role in melanoma development/progression and chemoresistance although their real impact is still unclear. Here, we show that BRAF(V600E) induces a chronic ER stress status directly increasing basal cell autophagy. BRAF(V600E)-mediated p38 activation stimulates both the IRE1/ASK1/JNK and TRB3 pathways. Bcl-XL/Bcl-2 phosphorylation by active JNK releases Beclin1 whereas TRB3 inhibits the Akt/mTor axes, together resulting in an increase in basal autophagy. Furthermore, we demonstrate chemical chaperones relieve the BRAF(V600E)-mediated chronic ER stress status, consequently reducing basal autophagic activity and increasing the sensitivity of melanoma cells to apoptosis. Taken together, these results suggest enhanced basal autophagy, typically observed in BRAF(V600E) melanomas, is a consequence of a chronic ER stress status, which ultimately results in the chemoresistance of such tumours. Targeted therapies that attenuate ER stress may therefore represent a novel and more effective therapeutic strategy for BRAF mutant melanoma.

High hERG1 expression in advanced melanoma

Cutaneous melanoma represents the main cause of death among skin cancers. The thickness of the lesion at diagnosis is one of the most important prognostic indicators for survival, which is good for thin melanomas (≤1 mm) and worsens as thickness increases. Nevertheless, it is not rare to observe disease progression of thin melanomas or, conversely, a good outcome for those melanomas considered to be at high risk, according to the classical prognostic criteria. In the present paper, we analysed for the first time the expression of the hERG1 protein, a potassium channel frequently overexpressed and misexpressed in cancers, in cutaneous melanocytic lesions. The analysis was carried out on archival samples relative to (a) typical melanocytic nevi, (b) atypical melanocytic nevi, (c) thin (<1 mm) melanomas from patients who survived at least 10 years after surgery, (d) thick (>4 mm) melanomas from patients who died for melanoma and (e) melanoma metastases. Samples were analysed by immunohistochemistry using an hERG1-specific antibody. We showed that primary cutaneous melanomas with a thickness greater than 4 mm as well as metastatic melanoma lesions are characterized by a high level of hERG1 expression. Conversely, thin melanomas and benign melanocytic lesions (e.g. typical and atypical melanocytic nevi) express hERG1 at significantly lower levels. Although still preliminary, the data presented here enable us to consider hERG1 as a novel candidate biomarker for aggressive melanoma.

Analysis of clinical, dermoscopic and histopathological features of primary melanomas of patients with metastatic disease--a retrospective study at the Department of Dermatology, Medical University of Graz, 2000-2010

BACKGROUND

Incidence rates of malignant melanoma have been increasing worldwide and metastatic melanoma is still a significant problem despite widespread prevention programmes.

OBJECTIVES

We made a systemic review of all metastasized melanoma patients treated at the Department of Dermatology, Medical University of Graz in the years 2000-2010 and looked at the kind of melanoma type, e.g. if it has been slowly growing superficial spreading melanoma (SSM) or fast growing nodular melanoma (NM).

METHODS

Histological slides and clinical images of patients treated at our department between 2000 and 2010, who received chemotherapy because of proven metastatic disease were analysed with regard to growth type of their primary tumours.

RESULTS

A total of 88 patients met the inclusion criteria. Mean age of all patients was 57 years (median 59 years, SD ± 15 years). Of these 88 patients 51 patients (58%) (28 male patients and 23 female patients) had SSM; mean age 58 years (median 58 years, SD ± 14 years) and 37 patients (42%) (18 male patients and 19 female patients) had NM; mean age 56 years (median 61 years, SD ± 17 years). Mean Breslow thickness in the SSM group was 2.26 mm (median: 1.6 mm, SD ± 2.11 mm). In the NM group, mean Breslow thickness was 4.59 mm (median: 3.50 mm, SD ± 4.07 mm). When separated by gender, 46 melanomas were seen in the male group (28 SSM and 18 NM) and 42 melanomas in the female group (23 SSM and 19 NM).

CONCLUSIONS

Our results showed that more than half of the patients with metastatic disease had SSMs and not, as suspected, NMs. As SSMs are growing over a longer period to become invasive and potentially metastatic, there might be a chance to focus primary and secondary prevention programmes not only on fast growing tumours but also on slowly changes of tumours.

BCL2 and BCLxL are key determinants of resistance to antitubulin chemotherapeutics in melanoma cells

Malignant melanoma is refractory to various chemotherapeutics including antitubulin agents such as paclitaxel. Previous studies have suggested a link between βIII-tubulin overexpression and paclitaxel resistance through alterations in the properties of the mitotic spindle. We found that paclitaxel treatment induced temporary mitotic arrest in 7 melanoma cell lines irrespective of the βIII-tubulin level, suggesting that βIII-tubulin had no significant influence on spindle properties. On the other hand, the amount of BCL2, an anti-apoptotic protein, was well correlated with paclitaxel resistance. Treatment of the paclitaxel-resistant cell lines with ABT-737, an inhibitor of BCL2 and BCLxL, or simultaneous knock-down of BCL2 and BCLxL dramatically increased the cells' sensitivity, while knock-down of MCL1, another member of the BCL2 family, had only a minimal effect. Our results suggest that the paclitaxel sensitivity of melanoma cells is attributable to apoptosis susceptibility rather than a change in spindle properties and that BCL2 and BCLxL play a pivotal role in the former.

Melanoma: from mutations to medicine

Melanoma is often considered one of the most aggressive and treatment-resistant human cancers. It is a disease that, due to the presence of melanin pigment, was accurately diagnosed earlier than most other malignancies and that has been subjected to countless therapeutic strategies. Aside from early surgical resection, no therapeutic modality has been found to afford a high likelihood of curative outcome. However, discoveries reported in recent years have revealed a near avalanche of breakthroughs in the melanoma field-breakthroughs that span fundamental understanding of the molecular basis of the disease all the way to new therapeutic strategies that produce unquestionable clinical benefit. These discoveries have been born from the successful fruits of numerous researchers working in many-sometimes-related, although also distinct-biomedical disciplines. Discoveries of frequent mutations involving BRAF(V600E), developmental and oncogenic roles for the microphthalmia-associated transcription factor (MITF) pathway, clinical efficacy of BRAF-targeted small molecules, and emerging mechanisms underlying resistance to targeted therapeutics represent just a sample of the findings that have created a striking inflection in the quest for clinically meaningful progress in the melanoma field.

Immunohistochemical double stains against Ki67/MART1 and HMB45/MITF: promising diagnostic tools in melanocytic lesions

Distinction between benign and malignant melanocytic lesions may be difficult by today's methods, even for highly skilled dermatopathologists, emphasizing the need for improved diagnostic tools. We have studied the discriminative abilities of immunohistochemical (IHC) double stains using the IHC markers Ki67 combined with MART1, and HMB45 combined with MITF. Paraffin-embedded tissue sections from 50 melanomas and 78 benign nevi were stained using a simple simultaneous IHC double staining technique. Both simple semiquantitative estimates of the immunopositivity in the deepest third of the lesions and full-scale quantitative measurements of the Ki67 and HMB45 indices were performed, and scores for melanomas and nevi were compared. The differences between melanomas and nevi were significant (P < 0.0001) using either analysis or stain. The misclassification rates for melanomas and nevi were generally lower for Ki67/MART1 stains than for HMB45/MITF stains. In the simple semiquantitative Ki67/MART1 analysis, the misclassification rates were 6% (2%-17%) for melanomas and 12% (6%-21%) for nevi. In full-scale quantitative analysis the corresponding rates were 4% (1%-14%) and 8% (4%-16%), and by combining Ki67 and HMB45 indices, the misclassification rates were 0% (0%-7%) for melanomas and 13% (7%-22%) for nevi. We conclude that both semiscale and fullscale quantitative analyses of Ki67/MART1 stains are valuable diagnostic tools to distinguish melanomas and nevi with a large degree of certainty. The HMB45/MITF stains may serve as adjuncts to predict malignancy and the diagnostic potential of combining the HMB45 and Ki67 indices are promising. The IHC double stains may potentially reduce misinterpretations of melanomas in histopathology.

Correlation of cell cycle regulatory proteins (p53 and p16(ink)⁴(a)) and bcl-2 oncoprotein with mitotic index and thickness of primary cutaneous malignant melanoma

The purpose of the study was to determine the frequency of expression p53 and p16INK4a proteins and bcl-2 oncoprotein in malignant skin melanoma and to determine their correlation with the proliferative index and tumor thickness. The study involved 53 patients: 27 (51%) male and 26 (49%) female. Mitotic index showed a correlation with p53 protein expression, a negative correlation with p16INK4a protein expression. Statistically significant correlations were determined between the Breslow tumor thickness, Clark invasion level and p53 protein expression, as well as Breslow tumor thickness and bcl-2 oncoprotein expression (p<0.05), whereas there was no correlation between the p16INK4a protein expression and melanoma thicknes and Clark invasion level. Overexpression p53 protein and bcl-2 oncoprotein, with the loss p16INK4a protein of expression in the nodular melanoma, confirms a frequent loss of function of these tumor suppressor gene and oncogene, and indicates a vertical tumor growth phase. The loss of tumor suppression function the p53 protein and bcl-2 oncoprotein overexpression in cutaneous melanoma correlates with larger tumor thickness, whereas the overexpression of mutated p53 protein and loss p16INK4a protein of expression indicate a higher proliferative tumour potential. Therefore, these evaluated proteins may be the aggressive biological tumour activity markers.

Tissue biomarkers for prognosis in cutaneous melanoma: a systematic review and meta-analysis

In the clinical management of early-stage cutaneous melanoma, it is critical to determine which patients are cured by surgery alone and which should be treated with adjuvant therapy. To assist in this decision, many groups have made an effort to use molecular information. However, although there are hundreds of studies that have sought to assess the potential prognostic value of molecular markers in predicting the course of cutaneous melanoma, at this time, no molecular method to improve risk stratification is part of recommended clinical practice. To help understand this disconnect, we conducted a systematic review and meta-analysis of the published literature that reported immunohistochemistry-based protein biomarkers of melanoma outcome. Three parallel search strategies were applied to the PubMed database through January 15, 2008, to identify cohort studies that reported associations between immunohistochemical expression and survival outcomes in melanoma that conformed to the REMARK criteria. Of the 102 cohort studies, we identified only 37 manuscripts, collectively describing 87 assays on 62 distinct proteins, which met all inclusion criteria. Promising markers that emerged included melanoma cell adhesion molecule (MCAM)/MUC18 (all-cause mortality [ACM] hazard ratio [HR] = 16.34; 95% confidence interval [CI] = 3.80 to 70.28), matrix metalloproteinase-2 (melanoma-specific mortality [MSM] HR = 2.6; 95% CI = 1.32 to 5.07), Ki-67 (combined ACM HR = 2.66; 95% CI = 1.41 to 5.01), proliferating cell nuclear antigen (ACM HR = 2.27; 95% CI = 1.56 to 3.31), and p16/INK4A (ACM HR = 0.29; 95% CI = 0.10 to 0.83, MSM HR = 0.4; 95% CI = 0.24 to 0.67). We further noted incomplete adherence to the REMARK guidelines: 14 of 27 cohort studies that failed to adequately report their methods and nine studies that failed to either perform multivariable analyses or report their risk estimates were published since 2005.

Melanoma biomarkers: current status and vision for the future

Melanoma is the leading cause of death from skin cancer in industrialized countries. Clinical and histological variables such as primary tumor invasion, ulceration, and lymph node status might fail to identify early-stage disease that will eventually progress. Tumor biomarkers might help to identify patients with early-stage melanoma who are likely to develop advanced disease and would benefit from additional therapies. These biomarkers offer the possibility of improved tumor staging through the molecular detection of microscopic lymph node metastases that are not visible on routine histological examination. We focus on biomarkers localized to the tumor tissue and those of prognostic value. We give an overview of the melanoma biomarkers that are most helpful for prediction of patients' outcomes, and discuss the primary melanoma biomarkers that have been shown to be of prognostic significance independent of primary tumor thickness and other common clinical prognostic indicators. Although such tumor-associated biomarkers are thought to have the greatest potential, a lack of reliable data makes their true clinical utility difficult to determine. We conclude that several biomarkers show promise in early studies; however, additional large-scale studies are warranted. We suggest cautious optimism for the field of melanoma biomarkers, which we expect to be translated into clinical practice over the next few years.

Melanoma genetics and therapeutic approaches in the 21st century: moving from the benchside to the bedside

Metastatic melanoma is notoriously one of the most difficult cancers to treat. Although many therapeutic regimens have been tested, very few achieve response rates greater than 25%. Given the rising incidence of melanoma and the paucity of effective treatments, there is much hope and excitement in leveraging recent genetic and molecular insights for therapeutic advantage. Over the past 30 years, elegant studies by many groups have helped decipher the complex genetic networks involved in melanoma proliferation, progression and survival, as well as several genes involved in melanocyte development and survival. Many of these oncogenic loci and pathways have become crucial targets for pharmacological development. In this article we review: (1) our current understanding of melanoma genetics within the context of signaling networks; (2) targeted therapies, including an extensive discussion of promising agents that act in the Bcl-2 signaling network; (3) future areas of research.

Microenvironment effects on promoting upregulation of matrix metalloproteinases in Bcl-2-overexpressing renal cell carcinoma as a response to doxorubicin treatment inducing the production of metastasis

Dysfunction in apoptosis has been suggested to play an important role in the development of a distant metastasis. The Bcl-2 gene plays a key role in the response to chemotherapeutic agents, and its upregulation protects the cells from apoptosis by inactivating the Bax proteins through heterodimerization of Bcl-2/Bax. However, there is no direct evidence showing that the upregulation of Bcl-2 increases the antiapoptotic effects against chemotherapeutic agents and is associated with the production of a distant metastasis. In this study, the role of Bcl-2 in the production of distant metastasis was investigated by examining the activity of caspase-3 and the expression of matrix metalloproteinases (MMPs) after transfecting the Bcl-2 gene into human renal cell carcinoma cells (SN12C). In addition, the production of a distant metastasis was examined in an orthotopic animal model. In vitro, the SN12C/smb2 cells were more resistant to doxorubicin (DXR) than the untreated parental cells. The IC50 of the SN12C/smb2 was 50% higher than that of the parental cells. In addition, the caspase-3 activity of the SN12C/smb2 cells was lower than that of the parental cells after the DXR treatment. On the other hand, there was no difference in the expression of MMP-2 and MMP-9 between the SN12C and SN12C/smb2 cell lines. However, the SN12C/smb2 cells had a higher metastatic potential than the parental cells in the orthotopic animal model. Unlike the results from the in vitro analysis, the expression of MMP-2 and MMP-9 in the kidney tumors produced by the SN12C/smb2 cells was higher than in the kidney tumors produced by the SN12C/vector. These results show that the upregulation of Bcl-2 in human renal cell carcinoma cells induces drug resistance to DXR. Moreover, Bcl-2 induced the expression of MMP in tumors grown in the orthotopic sites even though no appreciable effects were observed in the in vitro condition. When the in vitro and in vivo data were combined, it appears that the Bcl-2 gene initially affects the response to DXR. The cells that survive the DXR treatment then have a chance to become metastatic by increasing the levels of MMP in an orthotopic environment.

Malignant melanoma: genetics and therapeutics in the genomic era

Cell for cell, probably no human cancer is as aggressive as melanoma. It is among a handful of cancers whose dimensions are reported in millimeters. Tumor thickness approaching 4 mm presents a high risk of metastasis, and a diagnosis of metastatic melanoma carries with it an abysmal median survival of 6-9 mo. What features of this malignancy account for such aggressive behavior? Is it the migratory history of its cell of origin or the programmed adaptation of its differentiated progeny to environmental stress, particularly ultraviolet radiation? While the answers to these questions are far from complete, major strides have been made in our understanding of the cellular, molecular, and genetic underpinnings of melanoma. More importantly, these discoveries carry profound implications for the development of therapies focused directly at the molecular engines driving melanoma, suggesting that we may have reached the brink of an unprecedented opportunity to translate basic science into clinical advances. In this review, we attempt to summarize our current understanding of the genetics and biology of this disease, drawing from expanding genomic information and lessons from development and genetically engineered mouse models. In addition, we look forward toward how these new insights will impact on therapeutic options for metastatic melanoma in the near future.